1. Technical Field of the Invention
The present invention relates to a method of manufacturing a device (for example, a liquid crystal display device) comprising thin film elements such as thin film transistors, and to a device manufactured by means of the method.
2. Description of the Related Art
Liquid crystal display devices, which are electro-optical devices, have features of being thin and lightweight and have low power consumption, and thus they are used for various electronic apparatuses, such as personal computers, mobile phones, digital still cameras, and liquid crystal televisions.
The liquid crystal display device is provided with pixel portions using active elements such as thin film transistors. As the thin film transistor constituting the pixel portion, the inversely staggered type (or bottom gate type) structure constructed by forming a gate electrode on a substrate and laminating a semiconductor layer such as a channel region, a source/drain region, or an insulating layer thereon is being widely employed.
A pixel circuit of the liquid crystal display device is constructed by combining elements such as a scanning line for supplying a signal to these thin film transistors and the gate electrode, a data line for supplying a data signal to the source/drain region, or a pixel electrode connected to the source/drain region for applying voltage to a liquid crystal layer. A substrate (an array substrate) has the pixel circuit formed thereon and a counter substrate has a counter electrode formed thereon, a color filter and a light shielding film (a so called black matrix) shielding the surroundings of the color filter, etc. are bonded together and a liquid crystal material is inserted and sealed therebetween, thereby constructing a liquid crystal panel. Then, the liquid crystal panel is provided with peripheral members such as a driving circuit or a backlight to construct a liquid crystal display device.
The aforementioned liquid crystal display device is generally manufactured by repeating many times a process for forming a thin film by means of the vapor phase deposition method (that is, the vacuum process) such as the CVD method or the sputtering method and removing (etching) the unnecessary portion of the formed thin film by means of the photolithography method.
However, in this conventional manufacturing method, there are disadvantages in that (1) since the process comprising the film formation and the etching is repeated many times, the manufacturing time is long, (2) since much of the formed thin film is removed, the utilization efficiency of raw material is not good, and (3) since waste such as the etching solution is excessively generated, the processing cost thereof is increased. These disadvantages make it difficult to reduce the manufacturing cost in the conventional manufacturing method. These disadvantages become more remarkable as the glass substrate to be a basic material becomes larger with increase in screen size of the liquid crystal display device.
The present invention has been achieved in consideration of the above disadvantages. It is therefore an object of the present invention to provide a method of manufacturing a device which makes it possible to reduce the manufacturing cost.
It is another object of the present invention to provide a device which makes it possible to realize lower cost.